Ausmus drove in his fourth run of the night with the game-winning single in the 11th inning, and the Astros overcame another blown save by Lidge to beat the Oakland Athletics 5-4 Tuesday night.
Ausmus also had an RBI double and a two-run homer, though none of that mattered when Mark Kotsay led off the ninth inning with a homer off Lidge, who was trying to close out a game for the first time since April, when manager Phil Garner demoted him from the role.
Lidge had pitched well lately as a setup man, allowing only one earned run in his last 19 2/3 innings. He's 0-for-3 on save opportunities this season.
"I've been feeling really good and I was still feeling good focus tonight," Lidge said. "I maybe got a little too overamped on an 0-2 pitch. I tried to throw too good of one and probably left it up for him a little bit too much."
Kotsay hit Lidge's third pitch, a hanging slider, into the right-field seats for his first home run of the season. Kotsay went 4-for-5, his best game since coming off the disabled list on June 1. He'd never faced Lidge.
"I've been watching him on TV," Kotsay said. "I knew he was a fastball, slider guy."
Ausmus was batting .244 with only nine RBI coming into the game. He went 2-for-3 with an RBI and a double against the Chicago White Sox on Sunday.
"I'm just swinging the bat better lately," Ausmus said. "That's it. I don't know why."
The Astros won for the third time in seven games, and Oakland lost for only the second time in its last 10.
"Obviously," Lidge said, "I'm happy with how the game ended."
Roy Oswalt struck out a season-high 10 for the Astros and hasn't won since May 12, a span of six starts. Houston had lost the previous five, though Oswalt had only dropped two decisions.
Dave Borkowski (1-0) shut out the A's in the 10th and 11th to earn the victory. That was OK with Oswalt.
"If the team wins, I win," he said.
Joe Kennedy gave up four runs and six hits and also had the biggest hit for Oakland before Kotsay's homer, a surprising two-run double during a three-run second inning. Kennedy later scored on Mark Ellis' single.
Oswalt used an effective curveball to shut down the A's after that, striking out four consecutive batters between the fourth and fifth.
Jack Cust and Kendall fanned in the sixth, giving Oswalt 10 strikeouts for the first time since Sept. 1, 2005, when he had 11 against Cincinnati. Oswalt needed 111 pitches to get them this time and Chad Qualls relieved him to start the seventh.
"I wanted to get late in the game," Oswalt said. "When you get a lot of strikeouts, that means you're throwing four or five pitches per batter and it's hard to get deep."
Dan Wheeler, deposed from the closer role after blowing a save last Thursday in Colorado, shut out the A's in the eighth before Garner turned to Lidge.
Garner said he's sticking with Lidge as his closer.
"He's been throwing the ball so well," Garner said. "He just tried to make a superhuman, unbelievable nasty slider (to Kotsay) and he doesn't have to do that. He just has to throw a nice one."
Kennedy appeared to be an easy out for Oswalt -- he hadn't even batted in a game since July 7, 2005, when he played for Colorado, and had struck out in 25 of his 88 career at-bats. But he hammered a 2-0 pitch over center fielder Hunter Pence to score Johnson and Kendall.
"I'm sure all the hitters were happy to see me do that," Kennedy said. "I was looking for a fastball and it hit my bat."
Kennedy went to third on Kotsay's infield single, then trotted home on Ellis' broken-bat single to left.
Chris Burke walked leading off the Astros' second and scored on Ausmus' one-out double to right. In the fourth, Burke singled and Ausmus followed with a homer just inside the foul pole in left.
Flustered by Oswalt, the A's mustered only two hits between their three-run burst and Kotsay's game-tying drive.
"He settled into a groove and he started throwing that curveball," Kotsay said. "He really pitched well towards the end."
- Biggio went 3-for-5 with two doubles to move within 17 hits of 3,000. He now has 655 doubles, two behind Nap Lajoie on the career list.
- Ausmus homered for the first time in 289 at-bats, the longest drought on the team.
- Kennedy's last hit came on June 20, 2005, against the Astros.
- Kennedy was the first Oakland starter in 12 games to give up more than two runs.
- Astros' pitchers had 18 strikeouts, tied for the most by an NL team this season.